Ice shelves on the Pine Island Glacier are torn, accelerating major glaciers in Antarctica

The Pine Island Glacier ends with ice shelves in the Amundsen Sea. These crevasses are near the ground line where the glacier contacts Antarctica. This photo was taken in January 2010 from the east side of the glacier to the west. The ice shelf lost one-fifth of its area between 2017 and 2020, increasing the speed of inland glaciers by 12%.Credits: Ian Joughin / University of Washington

Over the decades, ice shelves have gradually become thinner, helping to control one of Antarctica’s fastest-moving glaciers. Analysis of satellite images reveals a more dramatic process in recent years. From 2017 to 2020, a large iceberg on the edge of the ice shelf collapsed and glaciers accelerated.

Floating ice shelves help control larger glacier masses, so recent speedups with weakened edges may shorten the timeline for the Pine Island Glacier to eventually collapse into the ocean. There is. A study by researchers at the University of Washington and the British Antarctic Survey was published in an open access journal on June 11. Science Advances..

“You may not be able to wait for the slow changes in Pine Island. In reality, things can go much faster than expected,” said a glaciologist at the University of Washington’s Applied Physics Laboratory. Said Ian Joffin. “The process we’ve been studying in the area has led to an irreversible collapse, but at a fairly cautious pace. If we lose the rest of the ice shelf, things are even more abrupt. May be. “

The Pine Island Glacier contains approximately 180 trillion tonnes of ice. This is equivalent to 0.5 meters (1.6 feet). Global sea level riseMany of Antarctica’s contributions to sea level rise are already involved in sea level rise, causing about one-sixth of the sea level rise each year, or about two-thirds of an inch per century, at this rate. Expected to increase. If the glaciers and adjacent Swates glaciers accelerate and flow completely into the ocean, releasing control of the larger West Antarctic Ice Sheet, the world’s oceans could rise a few feet in the next few centuries.

these Glacier As a result, it has been attracting attention for decades. Ice shelf The warmer current melted the underside of the ice, making it thinner. From the 1990s to 2009, the movement of the Pine Island Glacier into the sea accelerated from 2.5 kilometers to 4 kilometers per year (1.5 to 2.5 miles per year). After that, the glacier velocity stabilized for almost 10 years.

The results show that what happened recently is another process related to glacier internal forces, Joughin said.

From 2017 to 2020, ice shelves on Pine Island occupy one-fifth of the area with several dramatic interruptions captured by the Copernicus Sentinel-1 satellite operated by the European Space Agency on behalf of the European Union. I lost it. Researchers analyzed images from January 2015 to March 2020 and found that recent ice sheet changes were not caused by processes directly related to ocean melting. ..

The ice shelves on the Pine Island Glacier in Antarctica lost about one-fifth of their area between 2017 and 2020 in three dramatic interruptions. The time-lapse video incorporates satellite images from January 2015 to March 2020. For most of the first two years, the satellite took high-resolution images every 12 days. For more than three years, I took images of ice shelves every six days. The image is from the Copernicus Sentinel-1 satellite operated by the European Space Agency on behalf of the European Union. Credits: Joughin et al./Science Advances

“The ice shelves appear to be torn as glaciers have accelerated in the last decade or two,” Joein said.

The two points on the glacier surface analyzed in the treatise were 12% faster between 2017 and 2020.

“The recent change in velocity is not due to thinning due to melting, but to loss of the outer part of the ice shelf,” said Joughin. “The increase in glacier speed is not catastrophic at this time, but if the rest of the ice shelf collapses and disappears, the glacier can accelerate considerably.”

It’s unclear if the shelves will continue to crumble. Other factors, such as the slope of the land beneath the glacier’s receding edge, also have an impact, Joughin said. However, this result changes the timeline of when the ice shelves on Pine Island disappear and how fast glaciers move, helping to contribute to sea level rise.

“The loss of ice shelves on Pineapple seems to be likely to occur within the next 10 or 2 years, as opposed to the melt-induced underground changes that have lasted more than 100 years,” said co-author and oceanographer. Pierre Dutrieux said. In the British Antarctic survey. “Therefore, it is potentially much faster and more abrupt.”

Ice shelves on Pine Island are important because the curved buttresses of Notre Dame Cathedral help control this relatively unstable West Antarctica glacier in a way that supports the mass of the cathedral. When these buttresses are removed, slow-moving glaciers flow faster into the ocean, contributing to sea level rise.

“Record of sediments before and after Matsushima Ice shelf “It shows that glacier fronts have been relatively stable for thousands of years. Until 2017, there were regular advances and divisions in about the same place, and then every year until 2020,” said Dutriyu. Said.

Photo: Spartan Glacier collapses

For more information:
The retreat of ice shelves has facilitated the recent speedup of the Pine Island Glacier, Science Advances (2021).

Quote: The speed of the major Antarctic glaciers (June 11, 2021) obtained from on June 11, 2021. The ice shelves on the accelerating Pine Island Glacier are torn. html

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Ice shelves on the Pine Island Glacier are torn, accelerating major glaciers in Antarctica

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